R/WLErel.R

In TAM: Test Analysis Modules

## File Name: WLErel.R
## File Version: 9.14

#####################################################
# computes reliability for one-dimensional WLEs
WLErel <- function( theta, error, w=rep(1,length(theta)), select=NULL)
{
    #--- select cases
    if ( ! is.null(select) ){
        theta <- theta[ select ]
        error <- error[ select ]
        w <- w[ select ]
    }
    #--- exclude missings
    res <- WLErel_exclude_missings(theta=theta, error=error, w=w)
    theta <- res$theta
    error <- res$error
    w <- res$w
    v1 <- weighted_var( x=theta, w=w  )
    v2 <- weighted_mean( x=error^2, w=w  )
    # WLE_Rel=( v1 - v2 ) / v1=1 - v2 / v1
    rel <- 1 - v2 / v1
    return(rel)
}